G. Robert Arrabito

Effects of Talker Sex and Voice Style of Verbal Cockpit Warnings on Performance

Objective: The effects of talker sex and voice style of verbal cockpit warnings on performance were investigated to help make warning messages distinct from speech on the flight deck. Background: Auditory warnings are used in aircraft to alert the crew to hazards and their associated levels of danger. Failing to comply with a warning has led to aviation incidents and accidents. Methods: Participants were required to monitor the auditory channel and identify the verbal warning while simultaneously performing a visual pursuit tracking task. A male and a female actor annunciated the warning words in three styles: monotone, urgent, and whisper. In Experiment 1, warning words were presented in quiet, and in Experiment 2, they were presented in a background of speech babble that simulated cockpit radio communication. Results: Experiment 1 showed that the monotone and urgent styles resulted in the fastest identification response time (RT) regardless of the talker and listeners sex. Experiment 2 showed that the male talker annunciating in either the monotone or the urgent style resulted in the largest proportion correct and fastest identification RT regardless of the listeners sex. Both experiments showed effects of word semantics on performance. Conclusion: Effective use of speech parameters and word semantics can increase the saliency of verbal cockpit warnings. Application: Potential applications of this research include improving the attention-getting capability of an alerting system, which could lead to increased warning compliance, potentially resulting in fewer incidents and accidents.

Sustained Attention in Auditory and Visual Monitoring Tasks Evaluation of the Administration of a Rest Break or Exogenous Vibrotactile Signals

Objective: Performance and mental workload were observed for the administration of a rest break or exogenous vibrotactile signals in auditory and visual monitoring tasks. Background: Sustained attention is mentally demanding. Techniques are required to improve observer performance in vigilance tasks. Method: Participants (N = 150) monitored an auditory or a visual display for changes in signal duration in a 40-min watch. During the watch, participants were administered a rest break or exogenous vibrotactile signals. Results: Detection accuracy was significantly greater in the auditory than in the visual modality. A short rest break restored detection accuracy in both sensory modalities following deterioration in performance. Participants experienced significantly lower mental workload when monitoring auditory than visual signals, and a rest break significantly reduced mental workload in both sensory modalities. Exogenous vibrotactile signals had no beneficial effects on performance, or mental workload. Conclusion: A rest break can restore performance in auditory and visual vigilance tasks. Although sensory differences in vigilance tasks have been studied, this study is the initial effort to investigate the effects of a rest break countermeasure in both auditory and visual vigilance tasks, and it is also the initial effort to explore the effects of the intervention of a rest break on the perceived mental workload of auditory and visual vigilance tasks. Further research is warranted to determine exact characteristics of effective exogenous vibrotactile signals in vigilance tasks. Application: Potential applications of this research include procedures for decreasing the temporal decline in observer performance and the high mental workload imposed by vigilance tasks.

Human Factors Issues with Operating Unmanned Underwater Vehicles

There has been a great deal of human factors research on unmanned air and ground vehicles, but there is very little research examining the unique human factors problems associated with unmanned underwater vehicles (UUVs). The lack of research is surprising considering the increased use and the envisioned future use of UUVs in military maritime operations. In this paper, it is argued that because the underwater environment is so harsh and challenging, operating UUVs presents human factors problems that are different from the challenges of surface unmanned systems. Several common human factors problems are discussed when using unmanned systems, including the loss of sensory cues and spatial awareness, the control of the remote vehicle, problems with situation awareness and workload, and problems with trust in automation. In each case, these issues are discussed with respect to underwater operations.

Mapping Ecologically to Modalities

Ecological interface design (EID) is an approach to designing user interfaces that is based on the objective of providing functional system relationships to users in ways that reduce perceptual load. While EID has strong methods for determining the needed functional relationships through the analytical methods of Cognitive Work Analysis (Vicente, 1999), relatively little attention has been paid to establishing the design mappings that reduce perceptual load. We propose that different kinds of information should be assessed for perceptual fit to various modalities. In particular, those mappings that combine appropriate forms of reference with strong perceptual affordances will likely be the most successful. A case study applying this approach to the design of a multimodal ground control station for uninhabited aerial vehicle control is discussed.

Proposed Techniques for Extending Ecological Interface Design to Tactile Displays: Using Tactile Cues to Enhance UAV Interface Design

There is little guidance for designers on how to map information requirements to tactile displays. In this paper, we propose new directions for carrying out the mapping of tactile displays based on semantic mapping techniques used in auditory and visual displays. We discuss these techniques in relation to the design of a multimodal ground control station (GCS) for unmanned aerial vehicles to improve the visually-dominated GCS interface. We hope that this approach will encourage the design of better, safer, and more intuitive UAV GCS interfaces to reduce the frequency of mishaps related to human error.

Authority Pathway: Intelligent Adaptive Automation for a UAS Ground Control Station

Defence Research and Development Canada has conducted a number of human factors analysis tasks and experiments to support the Canadian Armed Force’s acquisition of an unmanned aircraft system for domestic and international operations. Experiments were run on a simulation-based UAS mission experimentation testbed. Results promoted the design and development of an intelligent adaptive interface called Authority Pathway that assists crew members with maintaining situational awareness and to adhere to rules of engagement when targeting. The Authority Pathway uses intelligent adaptive automation technology to adapt to dynamically changing mission goals, provide a variety of views for different users, and allow for varying levels of automation to be consistent with future requirements. Advantages and disadvantages of the Authority Pathway are discussed.

Effects of vibrotactile stimulation for sustaining performance in a vigilance task a pilot study

Supervisory control of uninhabited aerial vehicles requires vigilance, also termed sustained attention. This pilot study investigated the efficacy of short duration vibrotactile signals presented on the waist at intermittent periods as a countermeasure for sustaining performance in auditory and visual vigilance tasks that were equated in discrimination difficulty. Performance with the vibrotactile stimulation countermeasure was compared against performance with a rest break countermeasure. Participants were randomly assigned to one of eight groups. The groups were defined by combinations of sensory modality (auditory or visual), and type of countermeasure (control, rest break, low vibrotactile signals, or high vibrotactile signals). For each sensory modality, participants performed a monitoring task that was comprised four 10-minute vigils. The administration of the rest break and vibrotactile countermeasures occurred following the third vigil for each sensory modality. The results of the pilot study showed greater performance improvement in the auditory modality than the visual modality. In the auditory modality, the two vibrotactile countermeasures appear to have some benefit for sustaining performance but not as much as the rest break, whereas, in the visual modality, the three countermeasures had no benefit for sustaining performance. These preliminary findings encourage further investigation of the efficacy of vibrotactile stimulation as a countermeasure for sustaining performance in a vigilance task for both auditory and visual modalities.

Multimodal Displays for Enhancing Performance in a Supervisory Monitoring Task: Reaction Time to Detect Critical Events

This study investigated the efficacy of a multimodal display ground control station (GCS) for the control of an unmanned aerial vehicle (UAV) to convey system faults and environmental hazards. The participant’s task was to fly a short UAV mission, detect critical events, and land safely in possibly strong turbulence and wind shear. While monitoring for critical events, the participant also carried out a secondary task. The GCS simulator was equipped with an auditory display that provided information on engine revolutions per minute (RPM), and a tactile display that provided information on attitude upset. Multiple performance measures were used to determine whether the auditory display and tactile display improved monitoring performance relative to a visual-only GCS display. Results showed that the auditory display resulted in significantly faster reaction times to detect critical events in engine RPM. However, the tactile display did not add any benefit to warn participants of attitude upset. The results should help further the understanding of multimodal display effectiveness to enhance situation awareness for improving operator efficiency on monitoring tasks in complex systems.

Three-Dimensional Auditory Display for Enhancing Detection of Passive Sonar Signals

Objective: The viability of a three-dimensional (3-D) auditory display for improving signal detection of passive sonar signals was investigated. Background: Sonar operators usually have difficulty detecting targets because the sound received by the hydrophone has a low signal-to-noise ratio when coupled with the operators headset that does not isolate well against the ambient noise. Methods: Release from masking was assessed by pairing a recording of a torpedo with diotic broadband pink noise that served as a masker, and a 400 Hz tone with the masker. Masked thresholds were measured for seven signal durations when each signal was presented dioticly and in 3-D auditory space at three positions on the horizontal plane. Results: The spatial separation of signal and masker yielded a significant improvement in detection. Conclusion: A 3-D auditory display is a viable technology that could lead to a significant improvement in release from masking. The magnitude of the masking level difference will vary with respect to the characteristics of the hydrophone signal and masker and the synthesis capability of the 3-D auditory display. Application: Potential applications of this research include enhanced auditory displays for processing passive sonar signals, leading to earlier detection of enemy targets.